Live Load In modjeski 2

[jenofstructures]

We have an instruction in the office that we must study bridge design

I found a reference done by Modjeski and Masters from AASHTO (and they are using AASHTO code of course)

It called "Comprehensive Design Example for Prestressed Concrete Girder Superstructure Bridge with Commentary"

I just want to ask, if some of you know the exact formula on how this reference got its Live load moment and shear stated on page 5-13
Its a table 5.3-1 having the Positive and Negative Moment of live load

Thank you in advance

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[bridgebuster]

The live load moments are based on the position of the truck and the lane load. Look at the attached file, which illustrates how they are positioned for maximum (+) & (-) moment & shear. Even though the sketches shown are for HS loading and not HL-93 the principle is the same.

 

[jenofstructures]

thank you very much, i will study this one

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[bridgebuster]

you're welcome. Good luck.

 

[cap4000]

The link below has the new HL-93 loads indicated.

http://dcalc.us/Tutorials/Chapter5.pdf

 

[jenofstructures]

@cap4000 thank you

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds